There is another post for date calculations in forms that is also important but my problem is that I am trying to idiot proof my forms because people can't seem to enter the date correctly. I realize that this is a PEBCAK (problem exists between chair and keyboard) problem but my fix to it is that I index the day of birth with a select list of 31, the month of birth with a select list of 12 and a year of birth. Then in a workflow I put them all together as a date. It is a bit obnoxious. If I could just concatenate the fields in an index or a merge form field it would be helpful.